The robotic garden tools, for example, but not limited to, robotic lawnmowers are widely used for grass cutting applications in a lawn. Typically, a robotic lawnmower is an autonomous robotic tool and uses a battery as the power source. Based on the operating load and duration, there is a need to recharge the battery of the robotic lawnmower periodically. As an autonomous robotic lawnmower work unattended, it is required to find a path to a charging station in case the battery power level falls below a threshold power level during operation.
There are many techniques which are currently used to find a path to the charging station. Firstly, an antenna built on the charging station may be used to navigate the robotic lawnmower to the charging station. However, the antenna may have a limited range in a vicinity of the charging station and thus, there is a possibility that the robotic lawnmower is may take long time to find the antenna signals. Another limitation is the complexity in manufacturing the antenna in a close proximity of a charging plate. This may increase the cost of charging plate and thus, the overall cost of the system may also increase.
Another technique employed for overcoming the above mentioned disadvantage is that the robotic lawn mower may follow one or more guide wires or a boundary wire to reach the charging station. However, the robotic mower may follow a same path each time and this may result in undesirable permanent tracks and/or makings on the lawn.
Another technique to find the path to the charging station may use a global positioning system (GPS), but such system has complexity of integrating the GPS system to the robotic lawnmower. Apart from that, the GPS system is expensive and difficult to install, which in turn may add to the overall cost of the robotic lawnmower. Alternatively, a local positioning system, which uses local services such as Wi-Fi or a cellular network, may be utilized. In this case, the robotic garden tool has accurate positioning data but has added limitations of circuits and interfaces which are needed to be added to the system, which may again increase the cost as well as complexity of the entire system.
In light of the foregoing, there is a need for an improved method and system to find a path to a charging station, which will overcome the disadvantages of complex integration, increased cost and permanent tracks on the grass surface.